This invention relates to a sealing and shielding structure for sealing gaps, for example, between a housing for an electronic apparatus, etc. and a lid thereof, and for shielding the electronic apparatus, etc. from electromagnetic waves.
Conventionally, sealants made of various resins, for example, a synthetic rubber O-ring provided with elasticity by rubber and a synthetic resin packing formed to fit some gaps, are known. These sealants, closely mounted in gaps, prevent anything from leaking out of housings and also prevent outside airborne particles and water vapor from entering the housing.
However, when these sealants are attached to housings for electronic apparatus, electromagnetic wave noise may invade the electronic apparatus or leak from the electronic apparatus, because these sealants made of elastic rubber are, in general, not provided with conductivity. The electromagnetic wave noise may be transmitted on signal conductors of the electronic apparatus and adversely affect other neighboring apparatus. Accordingly, a conductive sealant which can shield electromagnetic wave noise is desirable.
One known conductive sealant is made of elastic material containing conductive metallic particles or carbon black particles as a conductive filler and can shield electromagnetic wave noise. However, such a conductive sealant has a problem: when conductive metallic particles, etc. are added to the elastic material in large amounts to increase the shielding effect, the conductive sealant becomes hard and brittle and cannot sufficiently function as a sealant.